Drive axle assemblies are well known, for example as disclosed U.S. Pat. Nos. 2,018,188, 2,187,843, and U.S. Pub. 2005/0006967. Electric axle assemblies, i.e. drive axle assemblies including an electric motor that either directly or indirectly drives wheel axles, are also well known. Known electric motor configurations are disclosed in U.S. Pat. Nos. 4,882,524, 7,233,090, and 9,083,226, and EP Pub. 3032717. Known electric axle assemblies can have a direct drive configuration such that the electric motor directly drives the wheel axles. These direct connection arrangements suffer from reduced efficiency as speed increases due to the electric motor drawing higher current while running at a higher rpm.
Planetary differentials and continuously variable transmissions are known components of drivetrains Electric axle assemblies that incorporate differential units and/or continuously variable transmissions are typically heavy and bulky. These arrangements are difficult to implement in electric axle assemblies due to the general need to reduce the weight and space required by electric axle assemblies. Other known electric axle assemblies that incorporate a continuously variable transmission typically require a clutch device, which increases the complexity of the overall assembly, as well as weight.
It would be desirable to provide a compact and efficient electric axle assembly.